Set Change Subaddress Index to u64::MAX - 1

This conflict was resolved:

```
diff --cc mobilecoind/src/payments.rs
index 6424c3f,c3b6f0ed..00000000
--- a/mobilecoind/src/payments.rs
+++ b/mobilecoind/src/payments.rs
@@@ -867,18 -876,17 +876,32 @@@ impl<T: BlockchainConnection + UserTxCo
              fog_resolver_factory(&fog_uris).map_err(Error::Fog)?
          };

++<<<<<<< HEAD
 +        // TODO: Use RTH memo builder, optionally?
 +
 +        let fee_amount = Amount::new(fee, token_id);
 +
 +        // Create tx_builder.
 +        let mut tx_builder = TransactionBuilder::new(
 +            block_version,
 +            fee_amount,
 +            fog_resolver,
 +            EmptyMemoBuilder::default(),
 +        )
 +        .map_err(|err| Error::TxBuild(format!("Error cretaing TransactionBuilder: {}", err)))?;
++=======
+         // Create tx_builder.
+         // TODO (GH #1522): Use RTH memo builder, optionally?
+         let memo_builder: Box<dyn MemoBuilder + Send + Sync> =
+             opt_memo_builder.unwrap_or_else(|| Box::new(EmptyMemoBuilder::default()));
+
+         let fee_amount = Amount::new(fee, token_id);
+         let mut tx_builder =
+             TransactionBuilder::new_with_box(block_version, fee_amount, fog_resolver, memo_builder)
+                 .map_err(|err| {
+                     Error::TxBuild(format!("Error creating transaction builder: {}", err))
+                 })?;
++>>>>>>> d991eee... API for generating burn txs in mobilecoind (#1872)

          // Unzip each vec of tuples into a tuple of vecs.
          let mut rings_and_proofs: Vec<(Vec<TxOut>, Vec<TxOutMembershipProof>)> = rings
```

There was a very small conflict which I resolved